In late years, ad hoc network system, of which a wireless terminal device each interconnects autonomously, is suggested. In the ad hoc network, the access point is not established, and the wireless terminal device each relays the packet, which is received from the wireless terminal device to connect with an own terminal device mutually, to an adjacency terminal based on path information, thereby forming the path (also called a channel or course). And, for example, sensor data which is measured at each wireless terminal device are relayed by one or more wireless terminal devices based on a generated path, thereby transmitting to an objective terminal (for example, patent literature one or two).
By such a system, the system failure such as breakdowns of the wireless terminal device and outage of dead battery of the wireless terminal device occur frequently. By the occurrence of the system failure, it is not possible that the wireless terminal device of the broadcast transmits and receives data, and the sensor data are not sent to the objective terminal. Therefore, handling (for example, repair, or substitution of the device and the battery) by the hands for the failure of the wireless terminal device is needed. However, when a wireless terminal device needing the handling is a majority, it is difficult to deal with the failure of a large number of wireless terminal devices immediately because the available staff may be limited.
Therefore, for example, the handling of the wireless terminal device of the minor fault is performed in a mass, not but immediately. In this way, it is planned that the handling for the failure is efficiency. For example, the priority for the handling of the failure is set based on the importance of the wireless terminal device. In the case of the ad hoc network, the substitute of the wireless terminal device of the broadcast is enabled by changing to another path relaying other wireless terminal device dynamically depending on the wireless terminal device which the failure has occurred. On the other hand, depending on the placement of the wireless terminal device, an alternative path may not exist. Therefore, for example, the importance of the wireless terminal device is calculated based on the number of the alternative paths and the number of the paths going by way of a target node.